Tougher air standards imposed this week give hope to Northern Kentucky residents who want to stop taking their vehicles for the biannual E-check tailpipe test.

But the new rules probably mean that the widely despised test will be around for a while in southwest Ohio.

And southwest Ohio motorists also may be forced in future summers to buy a more expensive blend of gas - and gasoline prices already are nearing record highs.

Cars are a focus of environmental regulators because vehicle exhaust is one of the major ingredients that forms ozone, an odorless, invisible gas that's a known lung irritant.

E-check may be phased out in Northern Kentucky, which set a three-year high for a gallon of regular unleaded Friday, because it was placed in the lowest violation category under the new rules issued Thursday. Because the region met the old ozone standard, Kentucky has the option to use - or remove - any programs to clean the air, including E-check.

But the Ohio side of Greater Cincinnati was out of compliance with the old anti-ozone rule. So southwest Ohio, which also saw soaring gas prices Friday, has to keep all programs in place, including some sort of vehicle testing.

"Our guidance is pretty clear; there will be no backsliding for those areas not in attainment with the old standard," said Jay Bortzman, chief of the criteria pollutants section of the U.S. Environmental Protection Agency's Region 5 office in Chicago, which oversees Ohio and other Midwest states.

That means cleaner burning fuel may become an option for Ohio drivers along with a continuing E-check, Ohio environmental officials said Friday.

"We may still do a vehicle emissions test that is not like E-check, or we may reinstitute it and turn to reformulated gas, or something else," said Heidi Griesmer, spokeswoman for the Ohio EPA.

"We feel that E-check works, and that it has been removing 100,000 tons of pollution each year. But everything will be on the table," she said.

A complicating factor for Ohio regulators is the contract with Envirotest Systems, the company that conducts the tests for the state, expires next year and has not been renewed.

While the "anti-backsliding" rule would apply to Southwest Ohio, Bortzman said that Clinton and Dearborn counties would be exempt because they are new additions to the violators list. So residents in those areas may not be forced to take their vehicles to E-check.

Alternatives studied

Even if E-check were abolished in Northern Kentucky, the region would still have to do something to control vehicle emissions.

The area could turn to a more stringent formula of reformulated gas instead of vehicle testing, although state officials said all options would be considered over the next three years.

"We're already paying a lot for gas, so what, they're going to gouge us more?" said Jimmy Combs, a marketing director from Newport.

"I'd rather pay that than the $20 bucks for a useless test."

Out of compliance

The renewed focus on the future of E-check was triggered after the federal EPA issued a list of 474 counties nationally out of compliance with a new tougher standard against ozone.

Eight Greater Cincinnati counties - Butler, Clermont, Clinton, Hamilton, and Warren in Ohio and Boone, Campbell and Kenton in Kentucky - plus one township in Dearborn County, Ind., were ruled to violate the tougher standard.

The new limits lower the amount of ozone, which retards crop growth and damages building materials as well as harming human health, allowed in the air. But they also lengthen the amount of time from one hour to eight hours that the air is measured.

Under the new rules, if the average level of ozone exceeds the 85 parts per billion standard at any time over a rolling eight-hour period, that day counts as a violation.

Four violations over a rolling three-year period put an area out of compliance with the standard.

Each state has three years to craft a plan for meeting the new standard. Greater Cincinnati then has until 2009 to get under the limit.

About reformulated gas

Reformulated gas was first sold in 1995. Its use is required by federal pollution law amendments in some areas of the country, but it was picked as an anti-pollution strategy in others (such as Northern Kentucky).

The gas is refined to remove certain pollution-causing hydrocarbons. The hydrocarbons are particularly prone to evaporate in hot weather. Heat and sunlight combine to convert the hydrocarbons into ozone.

Additives also are put into reformulated gas to boost its octane, making the fuel burn more cleanly and also prevent your car engine from knocking. (Knocking, which can cause engine damage, is caused when the gas is ignited by the compression of the engine's pistons rather than by the firing of the spark plugs.)

The additives for reformulated gas can include:

Ethanol, an alcohol typically made from corn. Ethanol is used in the reformulated gas used in Northern Kentucky.

MBTE, which is created from methanol (another kind of alcohol). MBTE is controversial because it is believed to cause cancer and it mixes with water (causing concerns when storage tanks leak and pollute groundwater or wells). Some states have banned MBTE.

The cleaner-burning fuel is only required in the summer months because that's when the weather conditions needed to form ozone occur in most of the country. In addition, the cleaner fuel makes engines hard to start when it's cold.

The added cost of making reformulated gas is pennies a gallon. But since 2000, the standards for reformulated gas were tightened; there have been sharp price spikes each spring. Some experts say this is because refineries try to sell all the winter gas they can before switching over to the summer blend - and that sometimes causes shortages that drive up prices strongly. (Price spikes are rare in the fall, when the winter blend is resumed, these experts note.)